6420320666 has 16 divisors (see below), whose sum is σ = 10139004960. Its totient is φ = 3040707600.

The previous prime is 6420320651. The next prime is 6420320707. The reversal of 6420320666 is 6660230246.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 338741 + ... + 357191.

It is an arithmetic number, because the mean of its divisors is an integer number (633687810).

Almost surely, 2^6420320666 is an apocalyptic number.

6420320666 is a deficient number, since it is larger than the sum of its proper divisors (3718684294).

6420320666 is a wasteful number, since it uses less digits than its factorization.

6420320666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27629.

The product of its (nonzero) digits is 62208, while the sum is 35.

The square root of 6420320666 is about 80126.9035093707. The cubic root of 6420320666 is about 1858.5984610837.

The spelling of 6420320666 in words is "six billion, four hundred twenty million, three hundred twenty thousand, six hundred sixty-six".